Train methodology
Rail Emissions Model (REM)
SQUAKE
SQUAKE's own passenger rail method. For every trip it uses the most specific factor available, from an operator's published figure down to a global average, and shows which one it used.
- Publisher
- SQUAKE
- Best for
- International rail travel and booking tools
- Result
- One total per trip, for all travellers
- Energy scope
- WTW
- Factor year
- Matched to the travel date
How it works
- A known rail distance is used as it is. A route path is measured without a detour factor. A straight-line distance gets a detour factor for the train type, from 1.08 for high-speed trains to 1.33 for trams.
- Route paths that cross borders are split by country, and each part gets the most specific factor available for that country.
- Seat class adjusts the result: first class counts 1.4 times an average seat and second class 0.9 times.
- Where REM models electricity itself, it uses the national grid average. Operator and national factors are used as published.
- Each result shows the tier, the factor, and the operator, country and year that were matched.
The tiers
REM uses the first tier that has data for the trip, starting with the most specific. Tiers 1 to 5 are live and all use secondary data, including Tier 1. The ranges are indicative, not statistical confidence intervals.
- Coming soon
Tier 0: Route-specific data
It will include Green Travel Data for journeys in Great Britain. SQUAKE is also exploring other operator-specific and route-specific sources.
- ±10 to 20%
Tier 1: Operator factor
The operator's published figure for the service and year.
- ±15 to 25%
Tier 2: Operator traction mix
The operator's traction mix (for example electric and diesel), with shared energy assumptions.
- ±15 to 30%
Tier 3: Country factor
A published national factor for the rail category and year.
- ±30 to 50%
Tier 4: Energy model
Traction shares × energy use × emission factors, for planning and screening. Tends to overestimate.
- ±50% or more
Tier 5: Global average
Used when nothing more specific exists.
Trip details used
When a detail is missing, SQUAKE uses the default.
| Detail | Default | Notes |
|---|---|---|
| Origin and destination | Required without a distance or route | Stations or addresses. |
| Rail distance | Measured from the route path, or estimated from the stations | Used as given. |
| Route path | None | Points along the route, used to measure the distance in each country. |
| Operator | None | Needed for tiers 1 and 2. |
| Train type | Average | For example high-speed, intercity, regional, commuter, tram or metro. |
| Traction | Diesel | Diesel, electric, hydrogen or HVO. Only used to choose between operator figures and for the energy model tier. |
| Seat class | Average | First, second or average. |
| Travel date | None | Matches the factors to the travel year. |
| Countries | None | Used for the country tiers. |
| Number of travellers | 1 |
What is included
Included
- Producing and supplying the energy, and running the train
- Electricity for electric trains (the national grid average where REM models it)
Not included
- Infrastructure, and building and maintaining trains
- Refrigerant leaks and diesel black carbon
Limitations
- Results are only as specific as the best tier available for the trip.
Sources
- Rail Emissions Modelrailemissionsmodel.com
Tiers, uncertainty, governance and assurance status.
- SQUAKE: Rail Emissions Model white papersquake.earth
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